refactor: remove bd daemon code from gastown

Remove all code that calls bd daemon commands, as bd daemon functionality
has been removed from beads:

- Delete internal/beads/daemon.go (CheckBdDaemonHealth, StopAllBdProcesses, etc.)
- Delete internal/beads/daemon_test.go
- Delete internal/doctor/bd_daemon_check.go (BdDaemonCheck health check)
- Remove bd daemon health check from gt status
- Remove bd daemon stopping from gt down
- Remove bd daemon cleanup from gt install
- Remove BdDaemonCheck registration from gt doctor

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/cmd/install.go

@@ -258,12 +258,6 @@ func runInstall(cmd *cobra.Command, args []string) error {
 	// Town beads (hq- prefix) stores mayor mail, cross-rig coordination, and handoffs.
 	// Rig beads are separate and have their own prefixes.
 	if !installNoBeads {
-		// Kill any orphaned bd daemons before initializing beads.
-		// Stale daemons can interfere with fresh database creation.
-		if killed, _, _ := beads.StopAllBdProcesses(false, true); killed > 0 {
-			fmt.Printf("   ✓ Stopped %d orphaned bd daemon(s)\n", killed)
-		}
-
 		if err := initTownBeads(absPath); err != nil {
 			fmt.Printf("   %s Could not initialize town beads: %v\n", style.Dim.Render("⚠"), err)
 		} else {